<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- sql-programming.qdoc --> <title>SQL Programming | Qt SQL 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtsql-index.html">Qt SQL</a></td><td >SQL Programming</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtsql-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <link rel="next" href="sql-connecting.html" /> <p class="naviNextPrevious headerNavi"> <a class="nextPage" href="sql-connecting.html">Connecting to Databases</a> </p><p/> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#topics">Topics:</a></li> <li class="level1"><a href="#database-classes">Database Classes</a></li> <li class="level2"><a href="#driver-layer">Driver Layer</a></li> <li class="level2"><a href="#sql-api-layer">SQL API Layer</a></li> <li class="level2"><a href="#user-interface-layer">User Interface Layer</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">SQL Programming</h1> <span class="subtitle"></span> <!-- $$$sql-programming.html-description --> <div class="descr"> <a name="details"></a> <p>This overview assumes that you have at least a basic knowledge of SQL. You should be able to understand simple <code>SELECT</code>, <code>INSERT</code>, <code>UPDATE</code>, and <code>DELETE</code> statements. Although the <a href="qsqltablemodel.html">QSqlTableModel</a> class provides an interface to database browsing and editing that does not require a knowledge of SQL, a basic understanding of SQL is highly recommended. A standard text covering SQL databases is <i>An Introduction to Database Systems</i> (7th Ed.) by C. J. Date, ISBN 0201385902.</p> <a name="topics"></a> <h2 id="topics">Topics:</h2> <ul> <li><a href="sql-programming.html#database-classes">Database Classes</a></li> <li><a href="sql-connecting.html">Connecting to Databases</a><ul> <li><a href="sql-driver.html">SQL Database Drivers</a></li> </ul> </li> <li><a href="sql-sqlstatements.html">Executing SQL Statements</a><ul> <li><a href="sql-types.html">Data Types for Qt-supported Database Systems</a></li> </ul> </li> <li><a href="sql-model.html">Using the SQL Model Classes</a></li> <li><a href="sql-presenting.html">Presenting Data in a Table View</a></li> <li><a href="sql-forms.html">Creating Data-Aware Forms</a></li> </ul> <a name="database-classes"></a> <h2 id="database-classes">Database Classes</h2> <p>These classes provide access to SQL databases.</p> <div class="table"><table class="annotated"> <tr class="odd topAlign"><td class="tblName"><p><a href="qsql.html">QSql</a></p></td><td class="tblDescr"><p>Contains miscellaneous identifiers used throughout the Qt SQL module</p></td></tr> <tr class="even topAlign"><td class="tblName"><p><a href="qsqldatabase.html">QSqlDatabase</a></p></td><td class="tblDescr"><p>Handles a connection to a database</p></td></tr> <tr class="odd topAlign"><td class="tblName"><p><a href="qsqldriver.html">QSqlDriver</a></p></td><td class="tblDescr"><p>Abstract base class for accessing specific SQL databases</p></td></tr> <tr class="even topAlign"><td class="tblName"><p><a href="qsqldrivercreator.html">QSqlDriverCreator</a></p></td><td class="tblDescr"><p>Template class that provides a SQL driver factory for a specific driver type</p></td></tr> <tr class="odd topAlign"><td class="tblName"><p><a href="qsqldrivercreatorbase.html">QSqlDriverCreatorBase</a></p></td><td class="tblDescr"><p>The base class for SQL driver factories</p></td></tr> <tr class="even topAlign"><td class="tblName"><p><a href="qsqlerror.html">QSqlError</a></p></td><td class="tblDescr"><p>SQL database error information</p></td></tr> <tr class="odd topAlign"><td class="tblName"><p><a href="qsqlfield.html">QSqlField</a></p></td><td class="tblDescr"><p>Manipulates the fields in SQL database tables and views</p></td></tr> <tr class="even topAlign"><td class="tblName"><p><a href="qsqlindex.html">QSqlIndex</a></p></td><td class="tblDescr"><p>Functions to manipulate and describe database indexes</p></td></tr> <tr class="odd topAlign"><td class="tblName"><p><a href="qsqlquery.html">QSqlQuery</a></p></td><td class="tblDescr"><p>Means of executing and manipulating SQL statements</p></td></tr> <tr class="even topAlign"><td class="tblName"><p><a href="qsqlquerymodel.html">QSqlQueryModel</a></p></td><td class="tblDescr"><p>Read-only data model for SQL result sets</p></td></tr> <tr class="odd topAlign"><td class="tblName"><p><a href="qsqlrecord.html">QSqlRecord</a></p></td><td class="tblDescr"><p>Encapsulates a database record</p></td></tr> <tr class="even topAlign"><td class="tblName"><p><a href="qsqlrelationaltablemodel.html">QSqlRelationalTableModel</a></p></td><td class="tblDescr"><p>Editable data model for a single database table, with foreign key support</p></td></tr> <tr class="odd topAlign"><td class="tblName"><p><a href="qsqlresult.html">QSqlResult</a></p></td><td class="tblDescr"><p>Abstract interface for accessing data from specific SQL databases</p></td></tr> <tr class="even topAlign"><td class="tblName"><p><a href="qsqltablemodel.html">QSqlTableModel</a></p></td><td class="tblDescr"><p>Editable data model for a single database table</p></td></tr> </table></div> <p>The SQL classes are divided into three layers:</p> <a name="driver-layer"></a> <h3 >Driver Layer</h3> <p>This comprises the classes <a href="qsqldriver.html">QSqlDriver</a>, <a href="qsqldrivercreator.html">QSqlDriverCreator</a>, <a href="qsqldrivercreatorbase.html">QSqlDriverCreatorBase</a>, <a href="qsqldriverplugin.html">QSqlDriverPlugin</a>, and <a href="qsqlresult.html">QSqlResult</a>.</p> <p>This layer provides the low-level bridge between the specific databases and the SQL API layer. See <a href="sql-driver.html">SQL Database Drivers</a> for more information.</p> <a name="sql-api-layer"></a> <h3 >SQL API Layer</h3> <p>These classes provide access to databases. Connections are made using the <a href="qsqldatabase.html">QSqlDatabase</a> class. Database interaction is achieved by using the <a href="qsqlquery.html">QSqlQuery</a> class. In addition to <a href="qsqldatabase.html">QSqlDatabase</a> and <a href="qsqlquery.html">QSqlQuery</a>, the SQL API layer is supported by <a href="qsqlerror.html">QSqlError</a>, <a href="qsqlfield.html">QSqlField</a>, <a href="qsqlindex.html">QSqlIndex</a>, and <a href="qsqlrecord.html">QSqlRecord</a>.</p> <a name="user-interface-layer"></a> <h3 >User Interface Layer</h3> <p>These classes link the data from a database to data-aware widgets. They include <a href="qsqlquerymodel.html">QSqlQueryModel</a>, <a href="qsqltablemodel.html">QSqlTableModel</a>, and <a href="qsqlrelationaltablemodel.html">QSqlRelationalTableModel</a>. These classes are designed to work with Qt's <a href="../qtwidgets/model-view-programming.html">model/view framework</a>.</p> <p>Note that a <a href="../qtcore/qcoreapplication.html">QCoreApplication</a> object must be instantiated before using any of these classes.</p> </div> <!-- @@@sql-programming.html --> <p class="naviNextPrevious footerNavi"> <a class="nextPage" href="sql-connecting.html">Connecting to Databases</a> </p> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. 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